1. Field of the Invention
The invention relates generally to conductor layers within microelectronic structures. More particularly, the invention relates to enhanced performance conductor layers within microelectronic structures.
2. Description of the Related Art
In addition to active devices (i.e., such as but not limited to transistors and diodes), as well as passive devices (i.e., such as but not limited to capacitors and resistors), microelectronic circuits, such as but not limited to semiconductor circuits, typically include patterned conductor layers that are separated by dielectric layers. The patterned conductor layers are generally used for connecting and interconnecting the active devices and the passive devices to provide fully functional microelectronic circuits.
As microelectronic technology, and in particular semiconductor technology, has advanced, and microelectronic device dimensions have decreased, the dimensions of patterned conductor layers that are used for connecting and interconnecting microelectronic devices within microelectronic circuits have also decreased. As a result of these decreased patterned conductor layer dimensions, various detrimental and undesirable effects may become more pronounced within microelectronic circuits. Included among these detrimental and undesirable effects are electromigration effects.
In an effort of provide for enhanced electrical performance within advanced microelectronic circuits, patterned conductor layers now routinely comprise copper containing conductor materials, insofar as copper containing conductor materials provide enhanced electrical properties (i.e., such as but not limited to electromigration resistance properties) in comparison with patterned conductor layers comprised of other conductor materials, such as aluminum containing conductor materials. While patterned conductor layers that comprise copper containing conductor materials are thus desirable within the microelectronic fabrication art, patterned conductor layers that comprise copper containing conductor materials are nonetheless also not entirely without problems. In particular, patterned conductor layers that comprise copper containing conductor materials are often susceptible to interdiffusion with surrounding dielectric materials, such as in particular surrounding silicon oxide dielectric materials. Such interdiffusion may compromise the integrity of both the conductor layer comprised of the copper containing conductor material, as well as the surrounding silicon oxide dielectric material.
Various microelectronic metallization structures having desirable properties, including copper containing metallization structures having desirable properties, are known in the microelectronic fabrication art.
For example, Koike, et al., in “Cu Alloy Metallization for Self-Forming Barrier Process,” Proceedings IEEE International Interconnect Technology Conference (IITC) 2006, pp. 161-63, IEEE 1-4244-0103-3/06, teaches a thermal annealing method for forming a barrier layer interposed between a silicon oxide dielectric layer and a copper containing conductor layer within a microelectronic conductor structure. The thermal annealing method uses a copper-manganese alloy seed layer for a plated copper containing conductor layer, where upon thermal annealing, manganese within the copper-manganese alloy seed layer reacts with an adjoining silicon oxide dielectric material to form a self aligned manganese oxide barrier layer.
In addition, Gambino et al., in “Optimization of Cu Interconnect Layers for CMOS Image Sensor Technology,” Advanced Metallization Conference (AMC) Proceedings 2005, pp. 151-56, teaches various configurations of copper interconnect structures that may be used for fabricating CMOS image sensors. Included in particular is a copper interconnect structure that includes a cobalt-tungsten-phosphorus alloy self-aligned capping layer.
Microelectronic conductor dimensions are certain to continue to decrease as microelectronic structure and device dimensions, including semiconductor structure and device dimensions, decrease. Thus, desirable are enhanced performance conductor structures for use within microelectronic structures, as well as methods for fabricating those enhanced performance conductor structures.